1. Field of the Invention
The invention relates to a fan driving signal generating apparatus and a method, and more particularly, to a fan driving signal generating apparatus and a method for generating a fan driving signal which varies with load current.
2. Description of the Related Art
The heat dissipating problem of an electronic device is more and more important nowadays due to the increasing of the data processing information and the processing speed of the electronic device. In addition, the integrated process had become advanced so that more electronic elements can be contained in the same electronic device. Therefore, the heat dissipating function of an electronic device should be improved, accordingly.
Generally, a way of performing heat dissipation in an electronic device is to provide a fan inside of, or configured close to the electronic device, creating air convection so as to dissipate heat.
A Hall sensor is usually equipped in the fan for sensing the magnetic field change when the fan is spinning and therefore generating a corresponding Hall signal. The fan driving circuit generates the driving signal according to the Hall signal. However, since the placement of the Hall sensor is usually fixed, for different operating conditions and environments, the driving signal cannot always drive the fan to achieve an optimum performance. The optimum performance may be, for example, the fan generates little noise or vibrations.
Therefore, a fan driving signal generating apparatus and method for generating a fan driving signal which varies with load current so as to achieve an optimum performance is highly required.